This invention relates to combined data and power transmission arrangements.
A combined data and power transmission arrangement may be used, for example, to distribute electrical power to various components in a vehicle, and also to transmit digital data signals between those components.
A problem with combining data and power transmission on the same physical cable is that fluctuations in the power supply level, caused for example by variations in the power drawn by the load, can affect the data signal levels, and hence can result in corruption of the data. The data signal can be isolated from power voltage variations by capacitively coupling it to the line. However, a side effect of this is that the average level of the data will then depend on the data pattern, thus making the data pattern-sensitive. The object of the present invention is to provide a way of reducing or overcoming these problems.